Raspberry Pi for this project?

Using Arduino Project Guidance
#1

In some of student hostels in Germany, I have seen students booking their washing slots (at the laundry rooms provided by the dorms) via the dorm's website. Say there are 200 students and there are 10 laundromats, a student books his desired slot, money is deduced from the student's prepaid account on confirmation of the slot. During his chosen slot, the student simply goes to laundry room, uses the machine designed to him (informed to the student on confirmation) and washes his laundry.

  • Every student books a slot from a different device(their own smartphones, laptops,..)
  • The slot management (which machine will be allotted to which student) is decided not by the student
  • Assuming the student can access this account using a smartphone app, the app reminds the student of the wash schedule 1 hour before the schedule begins. The app also informs the student when his schedule ends

Now, if I want to replicate such a system for a small dorm of 20 students and 2 laundromats using arduino (even for the sake of argument), how can I proceed?

I can use relays to control the power supply to the machines. With/without RTC I can control for how long the machines can be used during a single wash. But I am confused with the networking part.

case 01 - should/must I use a Raspberry Pi? or case 02 - can I use the wifi shields with arduino and handle the services (like the 3 features mentioned above) using actual web servers? case 03 - Are actual web servers necessary. Why not make use of the local/dorm's wifi network to machines, manage the slots, deduce payment/wash credit?

I would really love to gain some knowledge on this. A little elaboration if possible would be helpful (on which case01/02/03 and why)

Regards

#2

The Arduino is useful when you need to control external devices or read data from sensors. But it has very limited memory and its not intended for managing large quantities of data.

My guess is a RaspberryPi would be much more suitable for what you want - though I would seriously consider a cheap laptop, just for the convenience. Put all your code and data on a new external hard drive and if the laptop dies you can just get another one.

Your description does not say whether your system needs to control the machines (to prevent unauthorized use). If you need to to that there may be a role for an Arduino as a “slave” of the main system. But connections that control the mains electricity system in a public place should be approved by a qualified electrician. And the entire control system might need to be approved by the liability insurers or some Government agency.

…R

#3

Hi, I'm new to Arduino just so you know.

If you are trying to replicate the whole system that you spoke about then I would say you will need a computer of some sort, laptop, desktop or server should all be possible. That will need to run the main program which controls a database to process the transactions and bookings.

It would probably be better if it was some form of a web server front end which would be easier for users as no software would need to be installed.

I would guess then that you could use an Arduino at each machine where it could have a number pad for the operator to enter a pin code that changes on each booking for security of each laundry machine.

The Arduino could then contact the server (will call it a server for ease) to confirm the pin for the allocation time is correct and then when the Arduino gets confirmation back enables the power on the machine for the required time.

This would be a big project where I think the server side would take up far more of your time than the Arduino.

#4

Thank you both for the replies. I can understand that the wifi shield is simply a communication interface. the program to collect & save data, verify data, book slots needs to written in some kind of server. Here, raspberry pi/laptop can be a server. Got it till now

  • Can arduino Yun replace raspberry pi?

  • Is it possible that I can use cloud services like Amazon's AWS to function as a server? (sorry, if this question is stupid. Just wanna know)

  • Even when using cloud services like AWS, do I need an Raspberry Pi to be used? (bear with me :) )

Controlling every machine with an Arduino as a slave

  • Do you mean that the slave arduinos will be directly interacting/connected (physically) directly with the washing machine's built-in circuit?

But connections that control the mains electricity system in a public place should be approved by a qualified electrician. And the entire control system might need to be approved by the liability insurers or some Government agency

Yes, I know. Too complicated. But I am only trying to understand how the system could be designed (I mean the logic, software-hardware-human interface, ...)

Thanks again

#5

As you read my comments, keep in mind that I am a strong Arduino supporter.

First thing, why are you bothering to consider anything other than a cheap PC? If this is to be a serious application there is nothing to be gained by saving 3 cents here and there at the expense of your own time and future maintainability.

AlleSl3Icut: - Can arduino Yun replace raspberry pi?

In my opinion, NO, not for the overall system. The Pi is a much more complete Linux device. If the role of the Arduino is just to interface with hardware on instructions from another PC then the Yun might be more convenient that (say) an Uno plus additional boards.

  • Is it possible that I can use cloud services like Amazon's AWS to function as a server? (sorry, if this question is stupid. Just wanna know)

You can write web applications and have them hosted on other computers - this is very common. Just Google web hosting. I don't know specifically about Amazon.

  • Even when using cloud services like AWS, do I need an Raspberry Pi to be used? (bear with me)

You will need some device with a browser to access the cloud. You could use a PI but you will have to add a screen and keyboard - which come as standard on a PC.

  • Do you mean that the slave arduinos will be directly interacting/connected (physically) directly with the washing machine's built-in circuit?

I was just asking a question about this. You are the person who knows whether it will be necessary.

I was not so much thinking of interfacing with the machine's control system as simply controlling the power so it cannot operate at all without authorization. As I said, you will need to ensure you comply with electrical safety regulations - so avoid controlling the hardware if you can.

...R

#6